Unlike the United States, Britain has no constitutional guarantee of press freedom. Parliamentary committees and the police are now exploiting that lack of protection to harass, intimidate and possibly prosecute The Guardian newspaper for its publication of information based on National Security Agency documents that were leaked by Edward Snowden. The New York Times has published similar material, believing that the public has a clear interest in learning about and debating the N.S.A.’s out-of-control spying on private communications. That interest is shared by the British public as well.

In the United States, some members of Congress have begun pushing for stronger privacy protections against unwarranted snooping. British parliamentarians have largely ducked their duty to ask tough questions of British intelligence agencies, which closely collaborate with the N.S.A., and have gone after The Guardian instead.

Alan Rusbridger, the newspaper’s editor, has been summoned to appear before a parliamentary committee next month to testify about The Guardian’s internal editorial decision-making regarding the Snowden information. Members of Parliament have also demanded information on the newspaper’s decision to make some of the leaked information available to other journalists, including those at The Times. That should be none of Parliament’s business. Meanwhile, Scotland Yard detectives are pursuing a criminal investigation into The Guardian’s actions surrounding the Snowden leaks.

These alarming developments threaten the ability of British journalists to do their jobs effectively. Britain’s press has long lacked the freedoms enjoyed by American newspapers. Now it appears they are less free from government interference than journalists in Germany, where Der Spiegel has published material from the Snowden leaks without incurring government bullying.

The global debate now taking place about intelligence agencies collecting information on the phone calls, emails and Internet use of private citizens owes much to The Guardian’s intrepid journalism. In a free society, the price for printing uncomfortable truths should not be parliamentary and criminal inquisition.